comedi: vmk80xx: fix transfer-buffer overflows

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: comedi: vmk80xx: fix transfer-buffer overflows The driver uses endpoint-sized USB transfer buffers but up until recently had no sanity checks on the sizes. Commit e1f13c879a7c ("staging: comedi: check validity of wMaxPacketSize of usb endpoints found") inadvertently fixed NULL-pointer dereferences when accessing the transfer buffers in case a malicious device has a zero wMaxPacketSize. Make sure to allocate buffers large enough to handle also the other accesses that are done without a size check (e.g. byte 18 in vmk80xx_cnt_insn_read() for the VMK8061_MODEL) to avoid writing beyond the buffers, for example, when doing descriptor fuzzing. The original driver was for a low-speed device with 8-byte buffers. Support was later added for a device that uses bulk transfers and is presumably a full-speed device with a maximum 64-byte wMaxPacketSize.

References

• https://git.kernel.org/stable/c/5229159f1d052821007aff1a1beb7873eacf1a9f
• https://git.kernel.org/stable/c/ec85bcff4ed09260243d8f39faba99e1041718ba
• https://git.kernel.org/stable/c/40d2a7e278e2e7c0a5fd7e997e7eb63945bf93f7
• https://git.kernel.org/stable/c/7a2021b896de1ad559d33b5c5cdd20b982242088
• https://git.kernel.org/stable/c/199acd8c110e3ae62833c24f632b0bb1c9f012a9
• https://git.kernel.org/stable/c/33d7a470730dfe7c9bfc8da84575cf2cedd60d00
• https://git.kernel.org/stable/c/278484ae93297b1bb1ce755f9d3b6d95a48c7d47
• https://git.kernel.org/stable/c/06ac746d57e6d32b062e220415c607b7e2e0fa50
• https://git.kernel.org/stable/c/a23461c47482fc232ffc9b819539d1f837adf2b1